491 E
CHO
S
OUNDER
I
NSTALLATION
M
ANUAL
Rev A
Part Number GM495
Northstar
a unit of Brunswick New Technologies Marine Electronics
30 Sudbury Road
Acton, Massachusetts 01720
www.NorthstarNav.com
Service: 978/897-6600
Sales: 800/628-4487
Table of Contents
SECTION ONE — Introduction
- - - - - - - - - - - - - - - - - - - - 1
Welcome to the Northstar 491
- - - - - - - - - - - - - - - - - 1
Who should read this manual
- - - - - - - - - - - - - - - - - 1
Scope of this manual
- - - - - - - - - - - - - - - - - - - - - 1
Installation considerations
- - - - - - - - - - - - - - - - - - - 2
SECTION TWO — Installing the transducer
- - - - - - - - - - - - - - 3
Safety considerations
- - - - - - - - - - - - - - - - - - - - - 3
Selecting a transducer
- - - - - - - - - - - - - - - - - - - - - 4
Installation considerations
- - - - - - - - - - - - - - - - - - - 5
Choosing a mounting location
- - - - - - - - - - - - - - - - - 5
Installing the transducer
- - - - - - - - - - - - - - - - - - - - 7
Maintaining the transducer
- - - - - - - - - - - - - - - - - - 8
SECTION THREE — Installing the 491
- - - - - - - - - - - - - - - 11
Safety considerations
- - - - - - - - - - - - - - - - - - - - 11
System components
- - - - - - - - - - - - - - - - - - - - - 13
Choosing a mounting location
- - - - - - - - - - - - - - - - 14
Mounting the 491
- - - - - - - - - - - - - - - - - - - - - - 14
Wiring the 491
- - - - - - - - - - - - - - - - - - - - - - - 15
Initial checkout
- - - - - - - - - - - - - - - - - - - - - - - 19
Installation test checklist
- - - - - - - - - - - - - - - - - - 20
SECTION FOUR — Troubleshooting and servicing the 491
- - - - - - 21
Common 491 installation problems
- - - - - - - - - - - - - - 21
The status LED
- - - - - - - - - - - - - - - - - - - - - - - 21
Getting technical support
- - - - - - - - - - - - - - - - - - 24
Ordering replacement parts
- - - - - - - - - - - - - - - - - 25
Servicing the 491
- - - - - - - - - - - - - - - - - - - - - - 25
Returning a 491 for service
- - - - - - - - - - - - - - - - - 26
APPENDIX A — Technical specifications
- - - - - - - - - - - - - - 27
Glossary
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - 29
Index
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 31
491 INSTALLATION MANUAL Revision A PAGE 1
SECTION ONE — Introduction
Welcome to
the Northstar
491
An echo sounder is a device that provides information about the water
directly beneath a vessel. The Northstar echo sounder system consists of:
•
the Northstar 491 echo sounder sensor
•
a Northstar navigation system such as the 962, 958 or 6000i
•
a transducer
The 491 can be used with either a single-element transducer or a
dual-element transducer. The 491 automatically pings both transmitters
at power-up to determine the number of transducer elements connected.
If a single element is detected, the 491 operates in single-frequency or
dual-frequency interleaved mode (as determined by the operator) at 600
Watts. If two elements are detected, the 491 uses both elements at 1000
Watts.
Installation and setup procedures are different for the two basic types of
Northstar navigators. The following terminology should be carefully fol-
lowed:
•
the term
961/962
indicates instructions that apply to the Northstar
961 and the 962 navigators
•
the term
957/958/6000i
is used for these units
•
the term
navigator
by itself identifies information that applies to all
units
Who should
read this
manual
This manual is for marine technicians who are installing the Northstar
491 and connecting it to a Northstar navigator and a transducer.
Scope of this
manual
In this manual, you’ll find information about the following:
•
mounting and wiring the 491
•
connecting the 491 to the Northstar navigator
•
installing a transducer (an overview is provided, but for such details
as wiring, see the documentation provided by the transducer’s man-
ufacturer)
SECTION ONE — Introduction
PAGE 2 491 INSTALLATION MANUAL Revision A
•
connecting the 491 to a transducer (see also the
Transducer Connec-
tor Instructions
—GM492)
•
troubleshooting and testing the system
•
technical specifications for the 491
For information about obtaining technical support and returning the 491
for factory service,
“SECTION FOUR — Troubleshooting and servicing the
491”
beginning on page 21.
For details about operating the 491, see the
Northstar 491 Echo Sounder
Operations Manual
(GM494) or Northstar 6000i’s Reference Manual, for
that product.
Installation
considerations
1. Check the shipping carton for any damage, and immediately report
any damage to the carrier. Save all packing material in case you have
to return the 491 to the factory for repair or evaluation.
2. Unpack the carton, and check its contents. You should have
received:
•
the Northstar 491 Echo Sounder
•
10-foot (3-meter) data cable to connect the 491 to the navigator
•
10-foot (3-meter) power cable for the 491
•
491 parts kit (containing transducer cable end connector, back-
shell, heatshrink tubing, and the
Transducer Connector Instruc-
tions
—GM492)
•
Northstar 491 Echo Sounder Installation Manual
(GM495)
•
Northstar 491 Echo Sounder Operations Manual
(GM494)
•
owner registration card
3. Fill out the owner registration card and mail it to Northstar.
4. Review all of the installation requirements as outlined in Sections
Two and Three.
5. Install the transducer, then terminate the cable (see ”Connecting the
491 to a transducer” starting on page 18).
6. Mount the 491. For instructions, see ”Mounting the 491” beginning
on page 14.
7. Connect the 491 to ship’s power and to the navigator. Connection
information begins on page 15.
With the vessel in the water, turn on the system and verify proper opera-
tion.
CAUTION!
The following list of installation considerations isn’t
a substitute for all the details in Section Three. To
ensure that you meet all critical installation parame-
ters, be sure to read that entire section and follow
all of its recommendations.
491 INSTALLATION MANUAL Revision A PAGE 3
SECTION TWO — Installing the transducer
Safety
considerations
WARNING!
Be sure to turn the power off before starting the
installation. Further, it is highly recommended that
you keep power off while you’re performing the
installation. If power is left on or turned on during
the installation, fire, electrical shock, or other seri-
ous injury may occur.
Be sure to ground the equipment to prevent electri-
cal shock and mutual interference.
Be sure the transducer outputs are tied together
before handling to avoid electrical charge build-up.
WARNING!
Be sure to use a 3-amp fuse. Using the incorrect
fuse can result in fire or damage to the 491.
CAUTION!
Mounting the transducer requires drilling holes
through the hull; make sure the installation does
not cause the vessel to leak. A thru-hull installation
should be performed by a professional installer. Do
not attempt this unless you are fully qualified.
Do not perform a thru-hull installation of the trans-
ducer when the vessel is actually in the water.
Immediately
after installing the transducer, be sure
to check for leaks, and don’t leave the vessel in the
water for more than three hours before checking it
again.
Northstar assumes no responsibility for improper
installation of a transducer.
NOTE:
Be sure that the transducer doesn’t interfere with
any of the on-board systems. Check all other sys-
tems to ensure that their performance doesn’t
degrade when the transducer is connected.
SECTION TWO — Installing the transducer
PAGE 4 491 INSTALLATION MANUAL Revision A
Selecting a
transducer
Northstar recommends using an Airmar transducer with the Northstar
491 echo sounder. The Airmar B260, B744 and P66 can be obtained from
Northstar as an installation kit with connectors installed.
A table of Airmar transducer elements is given below to assist in evaluat-
ing characteristics of other Airmar transducers.
Dealers can also purchase quantities of transducers directly from Airmar
Technology Corporation at:
Airmar Technology Corporation
35 Meadowbrook Drive
Milford, New Hampshire 03055-4613
Phone 603/673-9570
Fax 603/673-4624
(www.airmar.com)
Table 1: Northstar-recommended transducers
Manufacturer Housing Power Frequency Northstar P/N
Airmar B260 1 kW 50/200 kHz TD1004
Airmar B744V/B44V (with
3-wire speed)
600 W 50/200 kHz TD1005
Airmar P66 600 W 50/200 kHz TD1006
Table 2: Airmar transducer elements
Transducer
element
Single
or Dual
element
Used in
Airmar
P/N
Acoustic
material
Beam
Width
(50
kHz)
Beam
Width
(200 kHz)
Rated
Power
50/200A Single B744V
B744VL
P319
B117
SS555
Urethane 45° 12° 600W
50/200A Single P66
P79
P74
LPU 45° 11° 600W
50/200B Single B256 Urethane 23° 5° 1200W
50AE/200Riq Dual B45
B250-B
B260
Urethane 19° 6° 1000W
SECTION TWO — Installing the transducer
491 INSTALLATION MANUAL Revision A PAGE 5
Installation
considerations
The following basic setup information isn’t a substitute for the installa-
tion instructions provided by the transducer’s manufacturer. To ensure
that you meet all critical installation parameters, be sure to read and fol-
low all of the requirements in their instructions. Northstar assumes no
responsibility for improper installation.
Choosing a
mounting
location
The two most common problems with echo sounder installations stem
from
electrical noise
and
cavitation
. Either of these situations can produce
poor performance.
Electrical noise occurs when the transducer cable is routed too closely to
noise-producing electronics, such as alternators, AC generators, radars,
etc. To avoid problems with noise, route the transducer cable by itself
(not in a bundle) and away from other wires or cables and the engine.
Cavitation can occur at high speeds. During cavitation, bubbles form
between the transducer and the water. When this happens, the trans-
ducer can’t get its energy into the water properly and won’t be able to
detect any echoes. To avoid cavitation, choose a mounting location with
good water flow all around it at all speeds.
Before any drilling or cutting takes place, carefully choose a mounting
location for the transducer that meets the following criteria (also see
Figure 1 on page 7), depending on the type of vessel:
•
the transducer is more than four feet away from the Northstar navi-
gator and other similar equipment, to prevent mutual electrical and
magnetic interference
• the transducer and its cable are as far as possible from other electri-
cal cables
• there is space above the transducer for the transducer’s stem, hous-
ing, and cable
CAUTION!
Do not mount the transducer:
behind strakes, fittings, or hull irregularities (mount-
ing in those locations may increase turbulence, aer-
ation, and cavitation) or near the keel
near openings for water intake or discharge
where it might be loosened by the vessel’s vibration
less than four feet away from the Northstar 961/962
processor or other similar equipment to minimize
interference
Choose the mounting
location to obtain the best
possible performance from
the transducer and the 491.
Take into account the
vessel’s maximum speed
when selecting a mounting
location, as turbulence can
affect echo sounding
capabilities.
SECTION TWO — Installing the transducer
PAGE 6 491 INSTALLATION MANUAL Revision A
• the path for running the transducer’s cable is reasonably direct—keep
in mind that the transducer cable is 33 feet long (10 meters). To pre-
vent damage, coil any excess cable and secure it
• water turbulence and noise are minimal, decreasing the amount of
bubbles passing over the transducer face
• the transducer isn’t behind hull irregularities or near eroding paint;
both indicate areas subject to turbulence
• the transducer is as far as possible from the engine or propellers, and
inboard of the lifting strakes
• the transducer always remains submerged and parallel to the water
surface
• the transducer is easily accessible from inside the vessel for adjust-
ments and maintenance
• the transducer’s ultrasonic beams aren’t obstructed by the keel, pro-
peller shafts, or any other part of the vessel
• the hull thickness falls within the limits in Table 3 below (all dimen-
sions are perpendicular to the waterline):
Table 3: Hull thickness limits
Model Minimum Maximum
AirMar B44V/B744V with fairing 6 mm (1/4 inch) 19 mm (3/4 inch)
AirMar B44V/B744V without fairing 6 mm (1/4 inch) 65 mm (2 1/2 inches)
AirMar B260 with fairing —— 45 mm (1 3/4 inches)
AirMar B260 without fairing 19 mm (3/4 inch) 114 mm (4 1/2 inches)
SECTION TWO — Installing the transducer
491 INSTALLATION MANUAL Revision A PAGE 7
FIGURE 1: Recommended installation locations for a transducer
Installing the
transducer
A flat-bottom hull provides the best environment for mounting the trans-
ducer: It provides a horizontal surface and a constant water flow over the
transducer, with little turbulence (see Figure 2 for the recommended
transducer incline angle). If the vessel has a deadrise angle greater than 5
degrees, mount the transducer on a fairing block to create a horizontal
surface and keep the transducer perpendicular to the waterline (see
Figure 3). You must order the fairing block, if needed, from the trans-
ducer’s manufacturer.
inboard
pressure waves
1/3 aft
full keel sailboat
displacement hull
(6-12")
fin keel sailboat
150-300mm
LWL
Best location for the transducer
(Load Waterline Length)
step-hull
outboard and I/O
planning hulls
SECTION TWO — Installing the transducer
PAGE 8 491 INSTALLATION MANUAL Revision A
FIGURE 2: Recommended transducer incline angle
FIGURE 3: Typical finished thru-hull installation with a fairing
block (Airmar B744V)
Maintaining
the transducer
Do not expose the transducer’s face or plastic housing to gasoline or
strong solvents, such as acetone. These solvents can penetrate and
degrade many plastics and reduce their strength.
Using anti-fouling
paint
The transducer should be coated with water-based anti-fouling paint to
prevent aquatic growth.
3˚ incline
1/3 aft
(Load Waterline Length)
LWL
angle
6–12mm (1/4–1/2")
backing
hull
fairing
multisensor
deadrise
fairing thickness
angle
slope of hull
parallel to
waterline
block
Deadrise angle and fairing thickness (B44V shown)
at narrowest point
SECTION TWO — Installing the transducer
491 INSTALLATION MANUAL Revision A PAGE 9
FIGURE 4: Anti-fouling paint areas (for Airmar B744V)
Cleaning a
transducer
To clean the transducer of heavy debris or foul sea growth, use a stiff
brush or putty knife, but don’t scratch the surfaces. Check the transducer
every few weeks, maximum.
Use sanding sparingly, as repeated sanding may affect the transducer’s
performance at high speeds. For lighter cleaning, the surface may be
wet-sanded with #220 or finer wet/dry sandpaper.
CAUTION!
Use special transducer paint. Other paints may
contain copper, which is conductive and can burn
out the transducer within minutes!
Anti-fouling paint (B744V shown)
Paint outside wall below the lower O-ring
including exposed end, paddle wheel cavity and paddle wheel
Paint exposed housing
lower
O-ring
and bore up 30mm (1-1/4")
paddle wheel
insert
housing
detail
SECTION TWO — Installing the transducer
PAGE 10 491 INSTALLATION MANUAL Revision A
491 INSTALLATION MANUAL Revision A PAGE 11
SECTION THREE — Installing the 491
Safety
considerations
WARNING!
Be sure to turn the power off before starting the installation.
Further, it is highly recommended that you keep the power
off while you’re performing the installation. If power is left on
or turned on during the installation, then fire, electrical
shock, or other serious injury may occur.
Be sure to ground the equipment to prevent electrical shock
and mutual interference.
Be sure that the voltage of the power supply is between 10
and 36 volts DC. Connecting to the wrong power supply can
result in fire or damage to equipment.
Be sure to use a 3-amp fuse. Using the incorrect fuse can
result in fire or damage to the 491.
CAUTION!
Keep the following safe compass distances from the 491:
1.0 m standard, 0.8 m steering.
CAUTION!
Be sure that the 491 doesn’t interfere with any of the
on-board systems. Check all other systems to ensure that
their performance doesn’t degrade when the 491 is turned
on.
If the vessel is out of the water when the echo sounder is
turned on, the transducer may be damaged.
CAUTION!
Do not open the 491. There are no serviceable parts inside.
Unauthorized tampering with the unit will automatically void
the warranty.
CAUTION!
Do not mount the 491 in the bilge. It is not designed to resist
heavy exposure to water and chemicals.
SECTION THREE — Installing the 491
PAGE 12 491 INSTALLATION MANUAL Revision A
SECTION THREE — Installing the 491
491 INSTALLATION MANUAL Revision A PAGE 13
System
components
Figure 5 on page 13 shows a configured 961/962 echo sounder system,
and Figure 6 on page 13 shows a configured 957/958/6000i echo sounder
system.
Figure 5: Echo sounder system components with the Northstar 961/962
Figure 6: Echo sounder system components with the Northstar 957/958/6000i
Northstar
961/962
display
Northstar
961/962
Processor
Shipʼs
Power
Northstar 491
Echosounder
GPS
Antenna
Transducer
10-foot power cable
(Northstar-supplied)
33-foot cable
(Part of transducer)
10-foot data cable
(Northstar-supplied)
Northstar
957/958/6000i
Navigator
Shipʼs
Power
Northstar 491
Echosounder
GPS
Antenna
Transducer
10-foot power cable
(Northstar-supplied)
33-foot cable
(Part of transducer)
10-foot data cable
(Northstar-supplied)
SECTION THREE — Installing the 491
PAGE 14 491 INSTALLATION MANUAL Revision A
Choosing a
mounting
location
Before any drilling or cutting takes place, carefully choose a mounting
location for the 491 module that meets the following criteria:
• where the transducer cable is kept securely away from other wires
• where the path for running the required electrical cabling is reason-
ably direct; keep in mind the different cable lengths
• where the 491 won’t be exposed to water
• where the status indicator (on the front of the 491) can be observed
for system testing and troubleshooting.
NEVER MOUNT THE 491 MODULE IN THE BILGE!
Mounting the
491
Figure 7 shows the mounting dimensions for the 491. The 491 may be
mounted either horizontally or vertically.
The mounting template supplied with the unit may be helpful in plan-
ning the installation and locating the mounting holes. The keyhole slots
make installation in hard-to-reach areas easier, but be sure to tighten all
mounting screws securely. Leave room for installing and removing cables.
FIGURE 7: 491 mounting dimensions and connector locations
2.90
2.90
0.75
6.24
0.190 dia.
0.360 dia.
0.190 dia.
Dimensions in inches
5.80
8.78
7.22
2.35
491
Echo Sounder
DATA
BNT Marine Electronics
30 Sudbury Road
Acton MA 01720
800-628-4487
www.NorthstarNav.com
8–36 VDC
8 Watts
STATUS
POWER
TRANSDUCER
#2 Speed +V
#3 Speed Gnd
#7 Thermistor
#6 Depth
Lo –
#9 Depth Shields
#1 Speed
Sig
#4 Thermistor
#5 Depth
Lo +
#8 Depth Hi +
#10 Depth
Hi –
Allow space
for cabling from
connectors.
SECTION THREE — Installing the 491
491 INSTALLATION MANUAL Revision A PAGE 15
Wiring the 491
The majority of installation problems are caused by shortcuts taken with
system cables. When installing the 491, be sure that you:
• assemble connectors carefully
• don’t make sharp bends in the cables
• leave service and drip loops, so that moisture won’t run down the
cables and into the 491 or the navigator
• tie-wrap all cables to keep them secure
• if cables are shortened, lengthened (not recommended), or re-termi-
nated, seal all wiring splices
• prevent interference from the transducer cable
Electrical power
requirements
The 491 is a negative-ground system that is reverse-polarity and over-
voltage protected. The unit requires 8 to 36 VDC power at 8 Watts.
Connecting the 491
to ship’s power
The connection between ship’s power and the 491 requires the 10-foot
(3-meter) power cable supplied with the 491.
The wires in the power cable must be connected as follows (black and
white can be connected together at the power source):
• Red → Positive (+) (fused lead)
• Black → Negative (–)
• Green → Ground (earth)
Connecting the 491
to the 961/962
The connection between the 961/962 and the 491 uses the 10-foot
(3-meter) data cable supplied with the 491. The cable connects to the P1
slot on the back of the navigator.
The cable is shipped with a round 6-pin connector that attaches to other
Northstar navigators. To install the 491 with a 961 or 962, you must cut
off and discard the 6-pin connector, and wire the cable as shown below.
Be sure you don’t cut off the 8-pin connector that plugs into the 491!
Figure 8 below illustrates the wiring at the 961/962 end of the cable.
Table 4 describes the pin’s functions.
CAUTION!
Make sure that fuse or circuit-breaker protection is
provided at the power source.
NOTE:
The 491 should be grounded to the vessel to eliminate interfer-
ence. Secure the green wire to the vessel’s nearest grounding
point. Without an earth grounding, performance may be degraded.
SECTION THREE — Installing the 491
PAGE 16 491 INSTALLATION MANUAL Revision A
FIGURE 8: Interface cable connection from 961/962 to 491
Violet
Black
Blue
Brown
Orange
White
Green
Red (not
connected)
961/962 P1 Connector Plug
(Wiring Side View)
Data Cable
16
17
18
13
6
5
4
3
2
1
14
15
11
10
9
8
7
12
Table 4: Cable connection between the 961/962 and 491
961/962 pin number 961/962 P1 signal name Cable wire color
9 Port 3 In (A) Blue
10 Port 3 In (B) Black
11 Ground Brown
12* Port 3 Out (A) Violet
12* Port 3 Out (A) White
13 Port 3 Out (B) Orange
16 Ground Green
** Not connected Red
* Connector P1, pin 12 on the 961/962 requires two connections from the cable.
**The red wire is not connected on the 961/962 end, and should be insulated and capped.
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